Abstract
In this paper, a method for walking stabilization control using a virtual plane method for up-down motion of biped robots is proposed. In the case of the up-down motion in whitch the height of the center of gravity (COG) is not constant, the Zero-Moment Point (ZMP) equation that shows the relation between the ZMP and the COG becomes linear time-variant. Using the proposed method, the ZMP equation is transformed into linear time-invariant. Therefore, the frequency analysis and parameter design of the walking stabilization control can be implemented easily even in the up-down motion. The validity of the proposed method was confirmed by some simulations and experiments.